It's get 404 error when I manual create /.well-known/acme-challenge this folder

    My system is Debian 9

    imscp 1.5.3

    Installed plugins: LetsEncrypt 3.6.0 and Phpswitcher 5.0.5


    I make /.well-known/acme-challenge this directory in htdocs.And I put txt file to acme-challenge this directory.But it's can't see this txt file.It's always show 404 error.How to fix it?